Empiro

It sounds like your transfer is less than efficient then -- the 1100 m/s I cited is for everything, including the escape burn (getting to Duna is less than 200 m/s on top of escape). Because of the Oberth Effect and because Kerbin is much larger than Duna, spending an extra 1000 on the escape will probably translate into a 2000 m/s capture burn. As for aerocaptures, no you don't need to perform an insertion burn first (which is why it's called an aerocapture). Assuming you did your transfer properly, your craft should enter Duna's SOI and then zip through. If you perform a correction (usually half way there), you should be able to tweak your path through Duna's SOI until it pass through the planet's atmosphere.

How much total Delta-V did you spend from LKO to get to Duna? As I stated above, if you're using much more than 1100 then your trajectory is sub-optimal, meaning that your capture will be more expensive as well. Aerocapture should save delta-V if you put your PE inside Duna's atmosphere from far away.

Yes, you should use a launch window planner like this one: http://alexmoon.github.io/ksp/ and launch at the correct time. It should take no more than a total of 1100 m/s to get to Duna, and you can aerobrake around Duna for very low cost

If you're already captured into orbit, then you want to raise your AP as high as possible, flip your orbit at the AP, and then bring it back down. Otherwise the best way is to enter the SOI in the correct place. All it takes is a slight burn when you're far away to determine which direction you'll be orbiting the planet. Also, it really doesn't matter which direction you're orbiting if you want to transfer back to Kerbin. I've never used Mechjeb, but perhaps it doesn't handle retrograde orbits properly or something, but it isn't too hard to do it by hand.

I've found that it's best to use a reverse gravity assist to get captured in the Jool system. Any of the three inner moons can work. It may take some time to set up, but as long as you make sure you come in at 0 inclination, you're almost guaranteed to be able to set up an effective gravity brake that lets you precisely control where you end up.

If in doubt, aim high and just skim the atmosphere. If your orbit doesn't close and you've passed PE, just do a bit of a retro burn. Note that it only takes about 80 m/s to capture into an elliptical orbit, and at that point, you can bring your AP down slowly with multiple passes.

In 1.0, there's been a general nerfing of SRBs. Previously they were extremely cheap (in comparison to engines + liquid fuel tanks), and provided decent delta-V. But now, I find it much harder to use them in a cost effective manner.

A lot of it will just come from practice -- when you went into the polar orbit, how far off were you? If you were off by less than 10 degrees, then it's not too bad. Try to see which direction you're off by, and retry the launch. One piece of general advice I can give is this: when you burn, you can change your orbit at every point except at your current location. This means that if you start your burn nowhere close to your target orbit, then you'll end up nowhere close to your target orbit.

Phase angle means the angle between the target and yourself when looking at a the Kerbol system (http://i.imgur.com/dXT6r7s.png). You can also use one of the transfer window planners, which tell you exactly which date it's best to launch from. Once the time is right, get into as circular of an orbit as you can. Then, create a maneuver node that's burns prograde the necessary amount. You should see that it leads to an escape trajectory. Then, drag the node back and forth so that your escape is about parallel to Kerbin's orbit in the prograde direction when you zoom out (if you're going to an inner planet like Eve, you want it to be retrograde).

You're definitely using Skippers in the lower stages -- your craft size is 380T, 9 skippers provide 5850 kN of thrust for a TWR of about 1.5 or so. And yes, you can drop the first two stages (for 5 orange tanks) and still have enough delta-V. In fact, you can drop the first two stages, make it to the Mun, land, get back into orbit, transfer to Minmus, land there, and then get back to Kerbin. Use this delta-V map: http://i.imgur.com/UUU8yCk.png (the only difference is that now, you only need ~3500 m/s to get into orbit instead of 4500 m/s).

To start with, switch the Mk55 Thuds with the Terrier or maybe a single Poodle (with a 2.5m fuel tank at the bottom to make things more aerodynamic). It will give your craft a bit more more crash tolerance too -- a single parachute might be too fast for the Hitchhiker can. You also have far more total delta-V than you need. Around 7000 should be plenty to get to the Mun and back with some room for mistakes. This means that you can remove your first two stages and still have more than enough for a Mun trip and return. Finally -- you're actually using Skippers all throughout by the look of things. I love those engines, but a pair of mainsails might be appropriate here, and it would let you reduce the width of your rocket

My practical advice is to ignore the atmospheric ISP. From a practical standpoint, you should be using engines with a high TWR and good sea level ISP when low in the atmosphere. By the time you switch to vacuum-only engines, the air will be thin enough that the ISP will be practically identical to the vacuum ISP.

I think a big source of the problem is that the buildings are so expensive -- even on hard mode it's not that hard to earn money with every single mission, but with a building being 100x the cost of a rocket, a huge chunk of your overall earnings has to be directed toward that. This makes the game feel grindy -- you already have proven that you can launch satellites to a specific orbit, land on the Mun, rescue a Kerbal, and proven that you can earn money while doing it, but you have to keep doing it to earn enough money. The second issue is much more subtle: it's that you spend money the same way you make money (i.e. you build rockets, which costs money, and use the rockets to do contracts, which makes money). You're either able to do that efficiently enough (which means that money quickly becomes not an issue, besides grinding away to upgrade buildings), or you can't, which means you'll quickly go bankrupt. There needs to be other rewards for success or failure that isn't tied to money. For example (and this doesn't mean I think KSP ought to do this, but just an example of how to make things more interesting), you're given a set of missions and a specific budget. However, it's designed in a way such that it's nearly impossible to accomplish all of the missions on the budget (and difficulty determines the budget). However, accomplishing certain missions might reward you with bonus science. Other missions might give you reputation (which can be spent on things like hiring better Kerbals, etc.), and other missions might slightly increase your budget for future time periods. Other rewards might even be totally non-gameplay related, such as learning about how the Kerbol system formed, and learn interesting facts about the bodies in the system). This presents the players with a meaningful tradeoff, while letting them decide where to take their space program. After the time period passes, you get judged on how well you did, and even just getting a good grade is rewarding to the player.

Alternatively, what if just the universal constant of gravitation G was much higher in the Kerbal universe? The planets and starts are made of the same stuff, have much lower mass, but the gravitational parameters would be as we see them. I did remember hearing that the Jool system would be stable if you made the planet and moons orbit around the barycenter (center of mass) of the whole system, instead of the exact center of Jool, though I haven't actually seen a simulation of that.

My biggest piece of advice: Use the NavBall! Switch it to surface mode and always burn against the green retrograde marker. Don't try to "wing it" by sight! The only thing you need to use sight for is judging approximate altitude above the surface. If you always burn against the retrograde marker, you'll kill off your lateral and vertical velocity. When you get close to the surface, keep the speed around 1-2 m/s (remember, burn against retrograde), and you'll be able to touch down gently.

Bigger rockets should be more stable than small ones (aerodynamic forces have relatively less of an affect compared to small rockets). However, there are a couple of possibilities: -As you burn fuel, your CoM is shifting, and is moving too low -You're pointing too far away from prograde -Your rocket is flexing, and bending too much in the airstream Adding more struts to the top of your rocket can help. As can turning off SAS. I've found that SAS offten causes wobble as it tends to over compensate. You don't need it at all. A well designed rocket automatically will point itself into the velocity vector.

There's a couple of rules of thumb, but for most Kerbin intercepts (which are equatorial), I launch just before the target passes overhead, and I launch into a lower orbit. This usually puts me slightly behind my target and I will quickly catch up. I have a steam guide here that goes over the easy case (the key is to be in circular orbits, and then drag the maneuver node back and forth to get the perfect intercept): http://steamcommunity.com/sharedfiles/filedetails/?id=289580294 There's different tricks you can do if you or your target are on significantly different inclinations or if your target is in an elliptical orbit. They're a bit advanced, but we can discuss those here if you wish.

If you add winglets or have a vectoring engine, it shouldn't be very difficult to get the degree turn. Also, I often turn off SAS after the turn, and let the natural aerodynamics take over (winglets really help here).

Your initial intuition is exactly correct: don't carry dead weight around. However (and it's not immediately obvious), don't forget that engines that aren't being fired at 100% are also dead weight. If you're throttling less than 100%, then consider taking some engines away and firing at 100%. That's less mass for the same thrust. In addition, half-empty fuel tanks are also dead weight. When you added more boosters, you're also hauling them for the same amount of time (or even longer if you throttled down). This is why asparagus staging is considered efficient: you drain just 2 tanks at a time, and ditch them (and the engines attached to them) as soon as they drain.

Using fins and turning off SAS might reduce wobble and let you get a cleaner turn. If you look closely at the navball you can see if your velocity prograde is slightly north or south. Just steer your rocket in the opposite direction to bring it back. You should be able to launch most of the time to an inclination of < 0.5 degrees.

I assume it's the smoke and other effects that you see when your rocket is firing its engines close to the ground.

I think that's more of an aerodynamic issue than anything else. I've noticed the instability of many rockets on the streams over the weekend, even when they're pointed prograde with stabilizing fins at the back.

After you escape Laythe, you need have about 1581 m/s left over (in the correct direction of course!) to escape Jool and transfer to Kerbin -- that's your target V(infinity). You solve for V in the equation above (and use 2800 m/s for V(escape)). You'll get the answer 3215 m/s (note the squares). Since you're already going 2000 m/s around Laythe, you need to spend 1215 m/s to get to 3215 m/s. Because Laythe has a tiny SOI compared to the size, you actually might be able to get away with less, as your test seems to indicate.

You can't gravity assist off of Jool since you're already in orbit around Jool. However, the quick answer is "not very much" past escape velocity if you're already in an orbit around Laythe (around 2000 m/s). The quickest way to calculate this is to use the equation for how much velocity you keep after escaping: V(infinity)^2 = V^2 - V(escape)^2. By using the transfer calculator, if you're in an orbit at Laythe altitude around Jool, it takes 1581 m/s, so that is how much speed we need after escaping Laythe. The escape velocity for Laythe is 2800 m/s, so you just solve and get 3215 m/s. Since you're already in orbit (2000 m/s) around Laythe, it means that you'll need just under 1300 m/s to make it. As an interesting note: this is less than you need if you're in Jool orbit, because of the Oberth effect. You can save a bit more if you instead use Tylo for a gravity assist, but not that much (since you'll need about 800 m/s to escape Laythe anyway). It sounds like your 3000 m/s should be plenty, in any case.

They still tend to collide with the center core though, but it won't destroy it because the relative velocities are low. I'm just glad this will be fixed for 1.0.